Sunday, 25 October 2015

What’s good about having diabetes

Getting Type 1 diabetes is seen by many people as a complete disaster. Effective treatment has been around for less than a hundred years and before that life expectancy after diagnosis was very short, with most patients dying before they had reproduced.

Although there are environmental triggers, the existence of diabetes is largely determined by a number of genes. How is it that these genes persist in a population over generations if many of the carriers of those genes do not reproduce?

We can infer an answer to this question by looking at single gene diseases in which the situation is clearer. For example thalassaemia, sickle cell disease, G6PD and other red cell disorders gave heterozygotes some resistance to the effects of malaria, the cystic fibrosis gene protected against cholera and the gene for haemochromatosis was useful in dealing with anaemia due to hookworm and other causes.

So these serious diseases persist because their effects were not all bad.

(Aside: I am aware of research showing how a gene with effects that are all deleterious at a young age can persist in a population, but I think this mechanism does not apply to diabetes. Genetic diseases that kill the elderly do not impede the survival of the gene. In fact they may enhance it)

Why do Type 1 diabetic genes persist in the population. The answer has to be that some of these genes confer a survival advantage. What advantage? I don’t know but there must be one. It may be that diabetic genes improve performance to a small degree in a broad range of activities and a specific advantage will never be determined. ( the evidence in favour of this will be in a later post) 

I used to think about what life would be like if I didn’t have diabetes. I wouldn’t have the hassle, but on the other hand I wouldn’t have the advantages. Maybe my skiing abilities would be much worse.

So don’t hate your diabetes. Learn to deal with the downsides, so that the good effects can shine through.

Sunday, 18 October 2015

Peripheral Neuropathy

Peripheral Neuropathy
Tests of peripheral nerve function used by some doctors can fail to detect what to patients are significant degrees of dysfunction.
I know this personally from being a patient with a massive lumbar disc herniation, pronounced to have normally functioning nerves by some doctors. Surgery removal of the offending bit of disc was spectacularly successful.
If you can do the following then you can be assured that your peripheral nervous system is functioning pretty well.

If you can't do this maybe you should think about whether you have a nerve problem and need to alter your management. Perhaps you should be more sceptical of advice you have previously received. It is well documented that many asymptomatic T1s, who are normal according to doctors physical examination, actually have low peripheral nerve conduction velocities and amplitudes. A doctor's opinion without nerve conduction studies is really not that reassuring.
Also note that riding a unicycle with a training wheel (aka bicycle) requires much much less nerve function.

Wednesday, 7 October 2015

Race nutrition

A few weeks ago I competed in the Kangaroo, Australia's premier long distance cross country ski race, and one of the world loppet series.
There were around a thousand entrants in the race over all classes.
I managed to be the 12th Australian home among those over 55, my best placing yet in my age cohort.
What did I have for breakfast before the race? A bowl of cornflakes and 2 cups of coffee. That is all. At the race itself I had a pre-race gel and some of the energy drink supplied by the race organisers. I would have been slower if I had started the race with a stomach full of rolled oats.

For those diabetics interested in maintaining their physical abilities as they age, I recommend Diabetics Athlete's Handbook by Sheri Colberg, although it has no specific information for those like me who also have Addison's disease. It has several sections on various matters relevant to older active diabetics, but doesn't go into the minutiae of what treatment strategies are associated with long term success in maintaining physical capabilities. Disappointingly, dosage recommendations are all in the form of a relative change in dose. There is no data on what absolute value of dosages are associated with long term success. Nonetheless I consider it essential reading.

Common sense says that if you want to be a healthy and active Type 1 diabetic when you are retired, you need to look at such people and follow a management plan which matches their's in diet, insulin dosage, and physical activity parameters. No randomised trial is going to measure such a long term outcome any time soon. Unfortunately, few medical researchers show any sign of appreciating the benefits of a case control approach.